WEATHER SNAP SHOTS: August 2006 Archives

These Beverly Shores, Indiana damage photos further underscore the fury of last Wednesday evening's microburst-generating thunderstorm. These are but the latest images to illustrate the devastating effect of last Wednesday evening's 100+ m.p.h. wind-generating thunderstorm complex as it roared onshore in northwest Indiana from Lake Michigan. Curt Kendall has sent along these photos from Beverly Shores, Indiana along with the following e-mailed comments:

"On Wednesday evening (August 23), I arrived home in Beverly Shores at 5:45. I took out my leaf blower and started blowing leaves off the steps and driveway. It started to sprinkle. At 6:00 the tornado sirens went off, I thought it seemed strange. At 6:01, I turned on the TV and an emergency announcement said that a tornado was headed toward Beverly Shores and Pines, Indiana and it would hit at 6:05. By 6:05, the winds were over 100 miles per hour, the rain was falling horizontally. Trees started to fall. My stainless steel gas grill was picked up and thrown across the yard. By 6:10, the winds slowed and my neighborhood devastated."

Many thanks to Curt for sharing his harrowing experience in one of the worst storms to sweep any section of our area in some time.

PHOTO COURTESY: Curt Kendall

Jack and Kate Anderson share this spectacular August 28, 2006 sunset on their lake in Watersmeet, MI. Seldom, they tell us, is the lake so calm you have such a spectacular reflection of the sky visible!

PHOTO COURTESY: Jack and Kate Anderson, Watersmeet, MI

We've posted images of the damage inflicted by the thunderstorms that swept into Michigan City and the areas surrounding last Wednesday. What we've not posted are distant views of the storms responsible for that evening's severe weather—at least not until now! National Weather Service Cooperative Observer Roberta Slaby sends us these eyecatching photos of the towering cumulonimbus cloud responsible which spawned the damage in Michigan City. This view of the thunderhead is from 60 miles away in Bourbannais. (For those outside the Chicago area viewing these photos and not familiar with our local geography, Bourbannais is located 48 miles south of Chicago's Loop in Kankakee County). These photos were taken around 6:30 pm--about an hour after the first supercells rolled into Indiana off Lake Michigan. Roberta points to the "alpenglow" effect evident in these remarkable shots---that's the orangish glow often seen on snow covered mountaintops especially in winter as the sun sets. Radar scans at the time this photo was taken indicated cloud tops near 50,000 feet and cloud to ground lightning discharges approaching 690 with this storm complex and other thunderstorms within a 225 mile radius of Chicago.
-Tom Skilling, Chief Meteorologist, WGN-TV

PHOTO COURTESY: Roberta and Ed Slaby, NWS Cooperative Observer, Kankakee, Illinois

Garry England shares these photos with us of the widespread damage at Michigan City's Washington Park Zoo in the wake of Wednesday's 106 m.p.h. thunderstorm gust. Wind velocity data off the National Weather Service's powerful Romeoville-based radar at the time signaled a strong rotary circulation near that area, and the National Weather Service is asking anyone with photos or video of a tornado or funnels to contact Warning Coordination Meteorologist Jim Allsopp: jim.allsopp@noaa.gov

--By Tom Skilling, WGN-TV Chief Meteorologist

Viewer Robert Fesus of Round Lake captured these amazing photos this morning of the storm cells that rolled through.

Valaparaiso was among the northern Indiana communities swept by Wednesday evening's powerful thunderstorms. These photos, submitted to us by Gerry Jasinski, show quarter-size hailstones covering the ground at his home. Hailstones in other sections of northern Indiana reached diameters as large as 2.5"—large enough to be termed "tennis-ball size".

PHOTO COURTESY: Gerry Jasinski, Valparaiso, Indiana

Cumulonimbus clouds produce the thunderstorms we experience on the ground. Larry Jahn of Macomb, IL photographed this cumulonimbus along a frontal system on a flight from Seattle to O'Hare around 4:30 pm Wednesday, August 2 while passing over Iowa. Ironically, it wasn't Larry's last encounter with this weather system. After a quiet arrival in Chicago shortly taking this picture, the same disturbance unleashed thunderstorms on Chicago "with a vengeance", Larry reports, canceling a connecting flight to Moline. Cumulonimbus clouds are the tallest on the planet and can reach altitudes of 70,000 ft. at times. The cloud pictured here appears to be about 30,000 ft. tall. Thanks for the photos, Larry!
-Tom Skilling

PHOTO COURTESY: Larry Jahn, Macomb, Illinois

The air heated by this Wyoming wildfire, captured by Tim and Sarah Sandman while driving toward their home in Buffalo, is behind the formation of the towering cumulus clouds evident at the top of the smoke plume. Heating encourages air to become buoyant and rise. Water vapor within the rising air cools with height, a process which leads to cloud formation as moisture condenses into droplets and becomes visible as a cloud. Thunderstorms have been known to develop above fires. Many thanks to Tim and Sarah for a chance to see wildfire-induced cloud formation through these photographs.
-Tom Skilling

PHOTO COURTESY: Tim and Sarah Sandman

Photos courtesy: Dan Alsager, Park Forest, Illinois

The deluges which swept sections of the Chicago metro area hit Chicago's South Side and south suburban areas especially hard Thursday. That's evident from Dan Alsager's rain gauge in Park Forest pictured here. Dan snapped these shots and relayed them to me at 6 p.m. Thursday evening. Park Forest wasn't alone with big rains. A late-arriving report on Thursday's rainfall from Barbara Rogers in Valparaiso, Ind., indicates her rain gauge had collected 5.4" of rain. Dr. Jim Angel, Illinois' state climatologist at the Midwestern Regional Climate Center indicates the 2.43" in 78 minutes at Midway Airport and on Chicago's South Side in repetitive ("training") thunderstorms Thursday evening works out to be a one-in-ten-year rain!
--Tom Skilling

A fast-moving, bow-shaped (on radar) squall line, which exploded to life in eyecatchingly unstable air overnight in Nebraska and Iowa late Wednesday night, raced eastward overnight and Thursday morning, embedded within a strong west to east jet stream traversing the U.S. The squall line's forward flank, shown in this photo taken by Debbie Stacoviak (thanks Debbie!) moving into west suburban Naperville around 9:30 a.m. Thursday morning, produced prolific lightning and driving downpours. Among the mid-morning cloud to ground lightning strikes reported beneath the storm's radar-scanned 55,000 ft.tall cloud tops, were two involving automobiles on I-55 and I-80. Lightning reportedly shattered one vehicle's windows near Gardner, well southwest of downtown Chicago.

PHOTO COURTESY: Debbie Stacoviak, Naperville, Illinois

Meanwhile, Jeremy Hylka of Joliet reported that downpours generated standing water and indicated transformers failed in the storm's ferocious lightning, prompting some power outages. Street flooding was rampant for a time late Thursday morning after nearly 2" of rain. The downpour-generating squalls then advanced into Indiana, reaching that area around midday. Behind the eruption of violent late-summer thunderstorms overnight were atmospheric energy levels over the western midwest which were "off the charts" by late Wednesday night at the same time dew points (a measure of atmospheric moisture) surged to steamy near 80-degree-levels over a corridor of central Illinois back into Iowa. Moisture build-ups of this magnitude, referred to as "dew point pooling", occur as winds converge on an area, concentrating moisture in a limited corridor and enhancing the upward air motion which sets storm formation in process. Vastly elevated energy ("CAPE", an acronym for "Convective Available Potential Energy") levels were calculated from weather balloon "soundings" over Iowa, Nebraska and extreme southern Minnesota, ominously suggesting an environment in which warm, humid air was likely to ascend at stunning rates, producing towering thunderstorms of noteworthy intensity in the process. Among PRELIMINARY rainfalls from Thursday morning's storms are:

2.00" Valparaiso, IN
1.85" Joliet
1.00" Romeoville (NWS-Chicago)
1.00" Wilmington
0.09" Midway Airport
0.18" Oak Brook
Trace O'Hare International

Canadian high pressure takes over in the days ahead, lowering temperatures and eventually dropping high humidity levels.

My meteorological colleague Richard Koeneman shares this shot with us Friday of summer haze in the Smoky Mountains of western North Carolina. High temperatures hit 90° at the 3,600-foot level southeast of Asheville while Asheville proper (at 2,100 feet above sea level) registered a 91° high. The air is humid with dew points Friday afternoon in the upper 60s.
--By Tom Skilling, WGN-TV Meteorologist

Many thanks to Bob Shah for this shot of Wednesday evening's approaching storms. A rainshaft is visible. Thunderstorms were proliferating explosively at the time of Bob's photo, literally developing overhead as Chicago's heat wave was preparing to break.
Tom Skilling

PHOTO COURTESY: Bob Shah

Extreme heat all too often departs grudgingly amid an explosion of thundery downpours. That was certainly the case Wednesday night. Some areas registered 1.50" of rain in 55 minutes time, enough to produce flooding and standing water. Thunderstorms, radar-scanned at 52,000 ft. tall, roared into the area, generating a breathtaking lightning show. At the height of the storms around 9-10 pm, lightning flashed continuously in many locations. Up to 1,200 cloud to ground strokes were measured within a 225 mile radius of Chicago--much of it focused in northern Illinois and Indiana (and that count doesn't include counting intra-cloud or cloud to cloud discharges, which aren't measured by lightning-detection systems) in a single ten minute period. Two of those discharges are captured in these dramatic photos provided to us by Chuck Hagen of Oak Lawn, Illinois. The cloud to ground strikes were taken by Chuck near a power station in Bedford Park at the height of last night's storms around 10 p.m. Preliminary reports indicate the top rain tallies in the area included 1.97" at Midway Airport and 2.01" at Willow Springs. The rains have ended the 6-day string of 90-degree plus days which included two days just a degree shy of 100-degrees. By comparison, Thursday's post-storm temperature at O'Hare is 72-degrees--a stunning 25-degree pullback from Wednesday's stifling 97-degree high and its dangerous 100-degree heat indicies!

-Tom Skilling

PHOTOS COURTESY: Chuck Hagen, Oak Lawn, Illinois

Nick Bilski shares these shots with us of ominous skies as thunderstorms erupted Wednesday night in the heat and humidity. Within hours, temperatures had plunged 15-20-degrees thanks to thunderstorm downpours and outflows.


PHOTO COURTESY: Nick Bilski

Another view of Wednesday's spectacular lightning show from Rob Anderson of Blue Island. Thanks Rob!

PHOTO COURTESY: Rob Anderson

These spectacular shelf cloud images submitted to us by John and Cathy Torchia as a mid-June thunderstorm moved into Peru, Illinois, may offer a glimpse of things to come over at least part of the Chicago metro area Wednesday night. Storms threaten to erupt along an incoming cold front, prompting severe thunderstorm watches mid-afternoon Wednesday just west of Chicago. They may be extended east into Chicago later this afternoon and Wednesday night. This means the area may undergo a thundery end stormy Wednesday night transition to much cooler air----temps will drop 20-degrees---for Thursday. Chicago and a wide swath of northern Illinois, far northwest Indiana, the southeastern half of Wisconsin, the southeast half of Iowa and northern third of Missouri are threatened by active, potentially severe thunderstorm clusters driven by excessive heat, 2+" of evaporated atmospheric moisture, converging low-level winds topped off by moderately strong westerly jet stream winds. Storms appear the greatest threat in the Chicago area beginning later this evening into Wednesday night. Development will be closely monitored because the existing atmospheric set-up has been known to set up "training" of thunderstorm cells over distinct corridors---referring to the arrival of repetitive waves of thunderstorms which produce huge rain tallies over comparatively narrow corridor. Note: Chicago's shoreline Lake Michigan water temperatures have PLUNGED 21-degrees in under 24 hours as Wednesday's gusty SW winds have push warm surface water away from the shoreline, promoting the temperatures slashing UPWELLING of deeper, much cooler water. The current lakeshore water temperature is 58-degrees----it was 79-degrees at its peak Tuesday.
-- Tom Skilling